68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8o 



toe failed to impress. Sole shorter than in pes, being wider than long. 

 As in the hind foot the two median toes are longest, the inner much 

 shortened and the outer somewhat shorter than the second and third. 

 All seem to be directed forward. 



In slenderness of the toes and narrow sole, these tracks bear a 

 striking resemblance to Ornithoides ? adamsi Matthew, from Nova 

 Scotia, but the greater number of toes and larger size of the present 

 specimen serves to distinguish the two genera. A comparison of the 

 two, however, leads me to wonder whether the Nova Scotian species 

 is not also four-toed, the outer toe failing to register as on the right 

 side of the specimen now before me. In his original description of 

 the species Matthew remarks: " It may be associated with 0. trifidus, 

 though the examples do not exhibit the characters of this genus 

 fully." ^ Matthew's inability to distinguish fore- and hindfoot im- 

 pressions adds a further resemblance to the specimen in hand. Its 

 reference to the present genus would seem most appropriate. 



Genus ANOMALOPUS, new genus 



Generic characicrs. — Quadrupedal. Four digits in pes. three in 

 manus. Forefoot smaller than hind, with hind placed in front of 

 fore. Outer toe of both manus and pes stout with rounded clawless 

 extremity directed outward and forward ; other toes acuminate. Inner 

 toe of pes short as in Agostopus. 



Genotype. — Anonialupiis siitrdevanti, new species. 



ANOMALOPUS STURDEVANTI, new species 

 Plate 20 



Type. — Catalogue number 11,577, U. S. N. M. Consists of a slab 

 of sandstone 475 mm. long having a trail of 13 imprints traversing 

 its entire length. 



Type locality. — Yaki Trail, Grand Canyon National Park, Arizona. 



Geological occurrence. — Supai formation. Pennsylvanian. 



Description. — Stride about 155 mm., width of trackway about 

 200 mm. Hindfoot: Length about 90 mm., width about 80 mm. Four 

 digits. First toe very short, heavy, with rounded extremity ; fourth 

 toe stout with rounded end much diverted outward from the others. 

 The fourth digit on the left hindfoot has a more pointed end and 

 projects more directly outward than the fourth of the right side. It 

 has the appearance of having suffered injury, which would fully 

 account for the differences noted. The second and third toes are long, 

 comparatively slender, with sharply pointed extremities. These me- 



* Proc. Trans. Roy. Soc. Canada, Vol. 10, 1904, p. 97. 



